The invention relates in general to the design of combustion engines, particularly compression-ignition internal combustion engines.
Emissions standards imposed on motor vehicle manufacturers are becoming increasingly severe, each change in a standard resulting in significant technical developments and in the use of additional and/or more complicated emissions-control devices which prove to be expensive.
Future standards are encouraging manufacturers especially to reduce the level of exhaust emissions of nitrogen oxides and particulates, notably in order not to clog the particulate filters too quickly, but the manufacturers are at the same time wishing to increase, or at least to maintain, the engine performance levels and drivability.